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Abstract Background and objectives: Air ionization (AI) may reduce the microbial content of the air 'and has bactericidal effects on some bacterial Strains, which is controversial. We conducted this study to evaluate the efficacy of Air ionizer in reducing the microbial content of air. Material and Methods: This experimental Study was carried out in Sadi Hospital of Isfahan. Two air ionizer were placed in two boxes. and the third box (Control) was empty. At the beginning of experiment and every 30 minutes up to three hours, we did air sampling in all groups. After taking the samples of every box, we incubated the samples and then performed colony counts and bacteriologic studies. Results: In all thirty-minute intervals, Colony Counts in all groups were lower than control group (P<0.05). 'Coagulase negative staphylococcus (CNS) was the most common bacteria isolated followed by Bacillus spp, Acinetobacter and Escherichia Coli, in control group, no colonization of Acinetobacter and E.coli is found in Air ionizer groups. Conclusion:Our findings qualitatively indicate that air ionization can reduce the microbial content of the air. Regarding the type of microbial air pollution and the amount of air cleaning needed, this method can be used solely or in combination with other air cleaning methods. Key words: air ionization, air cleaning air bacteria.

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Abstract Background and objectives: A Nosocomial infection is one of the Leading problems causing high mortality among hospitalized patients. This study aimed at confirming the concurrence of Nosocomial infections with microorganisms spreading in the air of hospital wards. Material and Methods: This study was conducted in 2009 at ValieAsr Hospital in Tehran, Iran. The Samples were taken from the air of different sections of the hospital both actively (with Quick-Tak, 30) and passively. After that, the samples were investigated for bacerial and fungal contamination and the results were compared with the results of Laboratory Studies of patients in different wards. Results: The Bone Marrow Transplant (BMT) ward shows the least fungal and microbial contamination whiles the Intensive Care Unit (ICU) the highest. The fungi are essentially Cladosporium and penicillium while the most well-Known organisms are Micrococcus and Staphylococcus epidermidis. Stenotrophomonas is seen in both blood and air culture in thorax surgery ward. Also, the concurrence of Staphylococcus epidermidis in the samples of the air and patients is considerable. Conclusion: There isn’t concurrence between the Nosocomial caused organism, apart from Stenotrophomonas and Staphylococcus epidermidis, and microorganisms isolated from patients. Because the bacterial and fungal organisms are in the air of Hospital, it is a necessity to install proper ventilation system. Keywords: Air Bacterial Contamination, Hospital, Nosocomial Infection

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Abstract Background and objectives: Anaerobic microorganisms, particularly bacteroides play an important role in causing Pulp and preapical diseases that lead to chronic abscess. we aimed at studying anaerobie infections in necrotic teeth having Acute and chronic clinical symptoms. Material and Methods: We examined 28 necrotic teeth of 28 patients for the purpose of anaerobic culture fifteen cases with acute clinical symptoms and 13 ones with chronic clinical symptoms. In total 38 root canals from 28 teeth were subjected for examination and sampling. The samples were cultured on thioglycolate medium, sent to laboratory and tested in anaerobic condition for identification of bacteria. Results: The results indicate that 76% of isolated bacteria from necrotic canals obligate anaerobes and 24% are facultative anaerobes. The most common isolated microorganisms are peptostreptococci, fusobacterium and bacteroides. Conclusion: These results are in agreement with the results of other researchers and it has been determined that bacteroids play an important role in destroying the necrotic teeth's bone. Anaerobic bacteria causing dental infactions are less identified and diagnosed, therefore, dentist and clinical lab should take this into account. Key words: Anaerobic Bacteria, Necrotic tooth, Pulp, preapical

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Abstract Background and objectives: Bile in healthy people is a sterile fluid and presence of any microorganism can be a marker for a disorder like cholelithiasis. The aim of this study was to determine the frequency of bacterial agents in the bile of patients with bilestone, malignant pancreatic and biliary diseases. Material and Methods: One hundred and two bile samples were obtained, during six months in 2011, from patients subjected to ERCP in Taleghani hospital, Tehran. First, Patient's clinical data, the type stone, and their disease status were studied, and then the microbiological investigations, such as culture, identification of the bacteria and detection of their counts, drug susceptibility testing and molecular tests (16s rDNA PCR) performed on all the samples. Higher than 103 bacteria counts for each sample, in the absence of underlying infections, was considered as stable colonization. We run SPSS version 13 to analyze the data. Results: Out of 42(41.1%) positive bile culture samples, 59 bacterial isolates are detected by conventional methods. Of culture negative samples, seven have bacterial DNA indicated by PCR method. The most isolated bacteria are E. coli (%34.4), Enterococcus spp. (%19.7), Klebsiella pneumoniae (%18) and Pseudomonas aeruginos (18%). The most frequent stones are cholesterol, black pigment and brown pigment, respectively. There is no significant association between the diseases, stones and types of bacteria. Previous antibiotic usage (44.6%) is meaningfully more than that of other biliary problems (p=0.01) Conclusion: The presence of bacteria, Escherchi coli and Entrococcus which are the most in bile samples, is considered as a risk factor in pathogenesis of biliary disorders. Further studies on the pathogenesis and pathophysiological effects of bacteria can help us to clarify the role of bacteria in producing bile stones. Key words: Bile stones, Bacteria, ERCP, Antibiotics.

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Abstract Background and objectives: Yoghurt is a milky, fermented and semi-solid production that is produced by Microorganism starters. These microorganisms are known as lactic acid bacteria, which are responsible for the formation of the tissue, scent and flavor of yoghurt. Their presence in digestive system makes people healthy. The aim of this study was determination of the number of Lactic Acid Bacteria and Yeasts in the combination of traditional yoghurts of villages of East-Azerbaijan- province. Material and Methods:In this study, we gathered 90 samples of traditional yoghurt from the villages of East- Azerbaijan province and transferred, in a standard condition, to the laboratory of pharmaceutical-applied research center of Tabriz medical science university. We used 10-6dilution to measure the number of lactobacilli in MRS Agar medium and 10-3 dilution to count the Yeasts in Saborodextros Agar medium. Then, the grown colony has been enumerated and the kind of bacteria was specified via biochemistry tests. Results: The mean number of lactobacilli in 1 ml of traditional yoghurts is about 62 × 106 CFU/mL and the number of Yeasts 41×104 CFU/mL. Delbrueckii and plantarum are the most common Lactobacilli, and Saccharomyces is with the highest frequency. Conclusion: According to findings of this research, there is considerable amount of microorganisms such as useful bacteria, in the traditional yoghurts of villages of East- Azerbaijan province. They have been used as a starter and probiotic in Dairy and milk factories to produce good production in the future. Key words: Lactic acid bacteria, East-Azerbaijan, Yoghurt, Yeasts

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Abstract Background and objectives: Genomic DNA extraction of bacterial cells is of processes performed normally in most biological laboratories therefore, various methods have been offered, manually and kit, which may be time consuming and costly. In this paper, genomic DNA extraction of Staphylococcus aureus was investigated using some laundry detergent brands available in Iran to achieve a rapid and cost effective method. Material and Methods: five-enzyme Taj brand, three-enzyme Saftlan brand ,and Darya and Pak brands without enzyme were used in the concentrations of 10, 20, 40, 80 mg/L. Afterwards, in order to evaluate the efficiency of extracted DNA in downstream processing, PCR test was performed for femA gene in the genome of Staphylococcus aureus. Results: DNA extraction using different concentrations of the brands show that extracted DNA using 40 mg/L Saftlan and Taj brand powders have the best results according concentration (µg/ml) and purity (A260/A280) parameters. These parameters are 387.5 1.88 (Taj), 254.1 2.80 (Softlan), 396.6 1.95 (Manual) and 423.3 2.2 (Kit), respectively. Afterward, the PCR test results by show that DNA extraction using laundry detergents has no effect on its efficiency in order to be used in downstream processes. Conclusion: These results indicate that the proper concentrations of laundry detergents can be used to extract genomic DNA with similar efficiency to kit and manual extraction methods. Key words: Bacterial genome, DNA extraction, laundry powder, PCR, Staphylococcus aureus

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Abstract Background and objectives: In this research, the formation of chitosan-TiO2 nanocomposite and its antibacterial effect on Escherichia coli and staphylococcus aureus was investigated Material and Methods: to study the results, we used Scanning electron microscopy (SEM) and transition electron microscopy (TEM) images, infrared (IR) spectroscopy and ultraviolet-visible. Optical Density (OD) was also measured by spectrophotometer then the effect of this nano composite, in the vicinity of aforementioned bacteria, on the sterilized gauze in solid Muller Hinton Agar and TSB liquid mediums was assessed Results: The mentioned nanocomposite was formed with the composition of 4mg/ml Chitosan concentration and 2% titanium dioxide concentration. Finally, we observed that this nanocomposite near 100% could prevent bacterial growth and in the presence of this material did not grow any bacteria. Conclusion: chitosan-Tio2 Nanocomposite can be useful on culture medium and sterilized gauze to control pathologic bacteria. Key words: nanocomposite, nanochitosan, titanium dioxide, antibacterial, sterilized gauze

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Abstract Background and objectives: Giardiasis is a parasitic infection of small intestine, with a worldwide distribution and the prevalence of Giardia in different parts of the world varies between 1 to 25%. Plants have the vast range of antimicrobial and antifungal activity that can be identified as alternative treatments for bacterial and parasitic pathogens, the same as Giardia. In this study, the methanol extracts of eucalyptus plants, Satureia hortensis and Heracleum glabrescens, on Giardia cysts were studied in vitro. Material and Methods: The cysts were isolated from the feces using a modified Bingham. After counting by Hemusytumetr, they were placed near by 200 mg / ml, 100 mg / ml and 10 mg / ml of the extracts prepared by DMSO for 30 and 60 minutes. Then, the number of dead and live cysts was counted under a microscope. Results: the fatality effect of the extracts in 60 minutes is higher than those of 30 minutes. The methanol extracts of Satureia hortensis, Eucalyptus and Heracleum glabrescens with the dilution of 200 mg/ml in 60 mins have the fatality effect of 84/3%, 63/3% and 44%, respectively. The highest fatality(84.3%) on Giardia cysts is related to Satureia hortensis with the dilution of 200 mg/ml in 60 mins and the Lowest(27%) is related to Heracleum glabrescens with the dilution of 10 mg/ml in 30-minute period. The significant relationship between the plant type and the fatality of methanol extracts is observed. Conclusion: the methanol extracts of Eucalyptus, Heracleum glabrescens and especially Satureia hortensis have anti-parasitic effects in the laboratory conditions. Thus, they can be used in the future, instead of the chemical antiparasitic drugs. Key words: Antibacterial Giardia lamblia cysts, Eucalyptus, Satureia hortensis, Heracleum glabrescens, Tonekabon

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Abstract Background and objectives: Meningitis is one of the most common infectious of the central nervous system (CNS), defined as an inflammation of the meninges. LIF is a potent pro-inflammatory factor. Cerebrospinal fluid (CSF) contains the growth factors and cytokines whose concentrations have been changed in most neurological diseases. The aim of this study was to determine the LIF concentration of serum and CSF in the children with bacterial meningitis. Material and Methods: In this study, the total protein concentration (TPC) and LIF in the serum and CSF of normal subjects and children with bacterial meningitis were measured by enzyme linked immunosorbent assay (ELISA). Results: the Values of serum TPC for children with meningitis (74.17±7.73 g/L) and controls (73.50±7.28 g/L) are not different significantly (P=0.7), and the TPC in the CSF of children suffering from meningitis and controls are 35±0.03 and 0.34±0.05 g/L, respectively (P=0.65). The concentration of serum LIF for children with meningitis( 253±19.14 ng/ml) is higher than that of controls (49.75±8.97 ng/ml), and also the concentration of LIF in the CSF of the children with meningitis (116.25±8.60 ng/ml ) is significantly higher than that of controls which is 9.04±1.83ng/ml (P<0.001). Conclusion: The LIF concentration in the CSF and serum may provide additional information in the differential diagnosis of meningitis. It is also concluded that LIF could be significantly involved in the pathophysiology of meningitis. Key words: Serum, Cerebrospinal fluid, Leukemia inhibitory factor, Children, Bacterial meningitis

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Abstract Background and Objectives: Concurrent with the development of new chemical drugs and antibiotics, their harmful effects are gradually emerged. Due to lack of harmful effects, herbal medicines have been used in the pharmaceutical industry. The aim of this study was the use of lavender essential oil as an herbal medicine for the replacement of antibiotics and chemicals. Material and Methods: In this study, the plant essential oil was isolated by drying and distillation method using Clevenger apparatus. The antibacterial effect of this plant was evaluated by using disc diffusion method and successive dilutions. In order to control the standard of the method, antibiotic discs and standard bacterial strains were used. Results: Based on the results, Proteus mirabilis and Enterococcus faecalis are , respectively , the most sensitive and most resistant bacteria to dilutions of 1, 1/2 and 1/4. Escherichia coli and Enterococcus faecalis, respectively, are the most sensitive and most resistant bacteria to the dilution of 1/8, 1/16, 1/32 and 1/64. MIC and MBC methods also show that all bacteria have the same minimum inhibitory and fatality concentrations except Enterococcus faecalis with minimum inhibitory concentration of 16/1 and minimum concentration fatality of 8/1. Evaluating the results of the disk diffusion method with antibiotic discs, we can observe the better effect of this plant in comparison with gentamicin and streptomycin discs on the growth of five strains of Staphylococcus aureus ATCC1885, Staphylococcus epidermidis ATCC 2405, Enterococcus faecalis ATCC2321, Escherichia coli ATCC 1652 and Proteus mirabilis ATCC 2601. Conclusion: the essential oil of Lavender can be used instead of chemical drugs to treat bacterial infections. Keywords: Lavandula, Anti-bacterial effects, Essential oils, Bacterium

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Abstract Background and Objective: Urinary tract infections and bacteremia are the major problems in renal transplant patients, which are mostly due to immunesuppressive regimens, surgery, and exposure to the germs in hospital. The aim of this study was to determine the prevalence of bacterial agents in the blood and urine samples of kidney transplant candidates. Material and Methods: In this one-year-long study, thirty-three renal transplant candidates were assessed for urine and blood cultures. One urine and blood samples from each patient before transplantation and three samples after transplantation were collected. The Samples, using standard microbiological methods, were investigated and infectious organisms identified. Results: In 133 urine samples, Escherichia coli (20.5%), Enterobacter spp. (5.3%), Klebsiella spp. (3 %) and Staphylococcus epidermidis (1.5%) were isolated. In the blood samples, Enterobacter spp. (9.1%), Escherichia coli (6.8%), Staphylococcus epidermidis (3.8%) and Klebsiella spp. (0.8%) were isolated. Conclusion: The results indicate that urinary tract infection was high in patients with transplanted kidney, and E. coli is the most common cause of this infection. Keywords: Kidney Transplantation Bacterial infections Urinary Tract and Blood Infections Escherichia Coli

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Abstract Background and Objective: Bacterial infectioins in particular meningitis, pneumonia and septicemia are still some of the most causes of mortalities in children.The aim of present study was to identify the most common bacterial agents causing infectionis in children under 14 and detection of antibiotic resistance paterns. Material and Methods: During two years,1897samples were obtained from the patients suspected bacterial infectioins. They were investigated for bacterial cultures, age, sex and antibiogram patterns. The species were identified by biochemical and serological methods. Results: Of 1897 samples, 563 (29.6%) had positve bacterial culture. Of these 74.7% were gram negative and 25.3% gram positive . The most common species were Escherichia coli(34.1%), Staphylococcus aureus (17.1%), Psuedomonas aeroginosa (12.4%), Kelebsiella (11%) and Staphylococcus epidermidis (5.7%). The most effective antibiotics against both gram positive and gram negative bacteria were ceftriaoxne, nitrofurantoin, nalidixic acid, amikacin and gentamycin. Conclusion: The gram negative bacteria in particular Escherichia coli, Psuedomonas aeroginosa and Kelebsiella are the predominant causes of bacterial infections in children under 14 in these regions. Most species showed a high relative resisitance to routine antibiotics such as ampicillin, trimethoprim and chloramphenicol. Key Words: Bacteria Infection Children Antibiotic

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Abstract Background and Objective: The excessive use of broad-spectrum antibiotics will lead to drug resistance of microorganism and specially nosocomial organisms. Because of high incidence of antibiotic resistance in hospitals, we aimed to study antibiotic resistance to gram negative bacteria. Material and Methods: This cross-sectional study was conducted on the data of biological samples (2006-2008), with positive culture result. Using antibiogram, microbial resistance to isolated microorganism was determined, and after culturing the samples, bacteria were identified by using differential media and antiserum. Then, antibiotic resistance was performed by disk diffusion. Results: The most common gram-negative microorganism obtained from all cultures was Ecoli with the lowest drug resistance to Nitrofurantoin. Conclusion: Based on the results, antimicrobial resistance pattern is not the same in different places and furthermore it is ever changing. Therefore, further research is needed to be done to have an accurate pattern of antibiotic resistance to provide effective treatment regimens. Key words: Antibiotic Resistance Disk Diffusion Gram Negative Bacteria Gorgan

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Abstract Background and Objective: This study was aimed to determine the extent of bacterial contamination and drug resistance patterns of isolates colonized in colonoscope and endoscope and in relevant personnel. Material and Methods: A total of 107 samples were obtained from staff of endoscopy and colonoscopy units (SEU and SCU) and gastroenterological imaging equipment. For isolation and identification of the bacteria, swab culture method and biochemical identification test were used, respectively. Antimicrobial resistance profiles, multi-drug resistance (MDR) patterns and phenetic relatedness of these isolates were also analyzed according to standard methods. Results: Most frequent pathogenic bacteria among the SEU and gastroenterological imaging related equipments were included S. aureus (20.8 % and 0 %) Enterococcus spp. (0 % and 5.4%) Pseudomonas spp. (0% and 13.5 %), and Clostridium difficile (0% and 12.5%). Analysis of resistance phenotypes showed a high frequency of MDR phenotypes among the SEU (82.1%), and also in endoscopes, colonoscopes, and other equipments (20%, 50% and 100%, respectively). Phylotyping of S. epidermidis isolates showed the role of staff in transmission of resistance strains to medical equipments and also circulation of strains with identical resistance phenotype among the studied samples. Conclusion: High frequency of pathogenic bacteria in colonoscopes, endoscopes and in the staff of endoscopy & colonoscopy units, and also contamination of these instruments with MDR pathogens emphasize the need for proper disinfection of endoscopes and colonoscopes and also instruction of staff in these units. Key words: Bacterial Contamination Endoscope Colonoscope Antimicrobial Resistance Gastrointestinal Disease.

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Abstract Background and Objective: This study was aimed to determine the extent of bacterial contamination and drug resistance patterns of isolates colonized in colonoscope and endoscope and in relevant personnel. Material and Methods: A total of 107 samples were obtained from staff of endoscopy and colonoscopy units (SEU and SCU) and gastroenterological imaging equipment. For isolation and identification of the bacteria, swab culture method and biochemical identification test were used, respectively. Antimicrobial resistance profiles, multi-drug resistance (MDR) patterns and phenetic relatedness of these isolates were also analyzed according to standard methods. Results: Most frequent pathogenic bacteria among the SEU and gastroenterological imaging related equipments were included S. aureus (20.8 % and 0 %) Enterococcus spp. (0 % and 5.4%) Pseudomonas spp. (0% and 13.5 %), and Clostridium difficile (0% and 12.5%). Analysis of resistance phenotypes showed a high frequency of MDR phenotypes among the SEU (82.1%), and also in endoscopes, colonoscopes, and other equipments (20%, 50% and 100%, respectively). Phylotyping of S. epidermidis isolates showed the role of staff in transmission of resistance strains to medical equipments and also circulation of strains with identical resistance phenotype among the studied samples. Conclusion: High frequency of pathogenic bacteria in colonoscopes, endoscopes and in the staff of endoscopy & colonoscopy units, and also contamination of these instruments with MDR pathogens emphasize the need for proper disinfection of endoscopes and colonoscopes and also instruction of staff in these units. Key words: Bacterial Contamination Endoscope Colonoscope Antimicrobial Resistance Gastrointestinal Disease.

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Abstract Background and Objective: Because of increased resistance to antibiotics, side effects of chemical drugs and importance of medicinal plants, we aimed to assess the antibacterial effects of methanolic extract of the Polygonumbistorta plant on the E. coli (ATCC 15224), Ps. aeruginosa (ATCC 25619), B. subtilis (ATCC 6633) and Stap. Aureus (ATCC 25923). Material and Methods: After preparing the extract, its antibacterial effect was assessed via gel diffusion method, using disk / well diffusion methods to determine MIC and MBC Results: MIC of methanolic extract was 78 µg/ml for E. coli, 63×103 µg/ml for Pseudomonas aeruginosa, 39 µg/ml for Bacillus subtilis and 31×102 µg/ml for Staphylococcus aureus Conclusion: In spite of resistance of gram-negative bacteria to chemical agents, polygonum bistorta methanolic extract could inhibit the growth of E.coli and P. aeruginosa. Key words: Antibacterial, Bistorta, Escherichia Coli, Pseudomonas Aeruginosa

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Abstract Background and Objective: Honey is a healthy and nutritious food that has been used for a long time as a treatment for different diseases. One of the applied properties of honey is its antimicrobial effect, which differs between different types of honey due to variation of phenolic and antioxidant compositions. This study aimed to assess antimicrobial effect of honey on Bacillus cereus, considering its chemical properties. Material and Methods: Three samples of honey (A1 and A2 of Khorasan Razavi Province and A3 of South Khorasan province (were prepared and studied in terms of chemical parameters .The antibacterial effect of honey was surveyed throughTurbidimeter using spectrometer with incubator time of 2, 4, 6, and 8hrs. the level of turbidity caused by bacterium growth was measured at different times with a wavelength of 600nm. Results: According to the study, the samples containing higher concentration of polyphenol has more antimicrobial activity. The samples of A2, A3, and A1 had the highest concentration of polyphenol, respectively. Conclusion: The results indicate the prebiotic effect of honey that can be justified by the presence of fructo-oligosacharids and vitamin B. Keywords: Honey, Bacillus Cereus, Antibacterial, Turbidimetry.

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Abstract Background and Objective: Cream pastry, because of their ingredients, making process and preserving conditions are susceptible to many types of microbes. This study was conducted to determine the level of contamination of pastry cream in Gorgan. Material and Methods: The randomly selected samples (N = 450) were tested according to national standards for microbial tests and then the data was analyzed. Results: The level of contaminations for Enterobacteriaceae and Staphylococcus aureus was 56% and 43.3%, respectively. The highest contamination occurred in summer with Enterobacteriaceae (N= 113) and the lowest in spring with Staphylococcus aureus (N= 40). Also microbial contamination in different types of cream pastries showed the maximum level in cream puff (90%) and the minimum level in roll pastry (30.6%). Conclusion: There is a significant difference in infection rate between different samples. The infection rate in this study is more than the prevalence of past studies. Keywords: Cream Pastry, Enterobacteriaceae, Staphylococcusaureus, Gorgan

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Abstract Background and objective: Antimicrobial and antiviral effects of Alloe Vera and Stachys inflata have been proved. We aimed to investigate the effects of extract of Alloe Vera and Stachys inflate on the growth of some bacteria to take the place of chemical drugs. Material and Methods: the extracts of both plants were prepared by maceration method different concentrations were prepared using Mueller Hinton agar medium and tested by Disc diffusion. Furthermore, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined by the Microdilution method. Results: The effect of Alloe Vera extract was significant on Staphylococcus aureus. MIC and MBC of Aloe Vera extract on Bacillus subtilis were obtained in 230 and 410 mg/ml, respectively, which were 500 and 714 mg/ml for Haemophilus influenza. The extract of gel of Alloe Vera had no effect on Bacillus subtilis. The extract of leaf and gel of Alloe Vera had an inhibitory effect on Haemophilus influenza and Pseudomonads aeraginosa. The extract of Stachys inflata had an inhibitory effect on Haemophilus influenza, but it did not have any on Pseudomonads aeraginosa. The Extract of Stachys inflata had no effect on Bacillus subtilis, while showing significant effect on Staphylococcus. Among antibiotics, Ofloxacin had an effect on Haemophilus influenza. The extract of both plants did not show any effect on Klebsiella pneumonia. Conclusion: Given the effect of Alloe Vera and Stachys inflata in laboratory conditions, we hope that these extracts will be used instead of chemical substances for making nutritional supplements to control human diseases. Key words: Alloe Vera, Antibacterial, Stachys Inflata, Extract

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Abstract Background and Objectives: Contamination of environment to lead and copper is rising due to human activities. One of the best methods to remove heavy metals from the environment is bacterial remediation. This study aimed to isolate bacteria and investigate the mechanism of lead and copper bioremediation. Material and Methods: Heavy metal resistant bacteria were isolated from contaminated wastewater samples. The isolates with high resistance to lead and copper were selected for further studies and bioremediation was assessed by atomic absorption spectrophotometer. To determine the functional groups to remove metals, FT-IR was employed. In addition, plasmid curing was studied to determine the location of the genes that are resistance to heavy metals. Results: Ten bacterial isolates that are resistance to heavy metals were isolated. Among these, MKH3 with the highest remediation activity removed %90 lead and %92 copper from the growth medium. The absorption mechanism of MKH3 indicated that the functional groups such as carboxyl, amide, carbonyl and hydroxyl were most effective for removal of heavy metals from the growth medium. The results revealed that heavy metal resistant genes may be located on plasmid DNA. Furthermore, molecular identification demonstrated that MKH3 was similar to Enterobacterhormaechei with 98% homology. Conclusion: Bacterium isolated from a contaminated site showed the ability to remove a high amount of lead and copper. Thus, MKH3 could be useful for the bioremediation of heavy metals, particularly lead and copper, from industrial wastewater and contaminated sites. Keywords: Biosorption, Bacteria, Lead, Copper, FT-IR